Gregory Chioniades (Greek: Γρηγόριος Χιονιάδης, romanized: Grēgorios Chioniadēs; c. 1240 – c. 1320[1]) was a Byzantine Greek astronomer. He traveled to Persia, where he learned Persian mathematical and astronomical science, which he introduced into Byzantium upon his return from Persia[2] and founded an astronomical academy at Trebizond.[3] Choniades also served as Orthodox bishop in Tabriz.